The present invention relates to a process for the subdivision of a long tape or string made of a gummy material into single portions; in particular, the present invention relates to a process operated in an industrial plant on a continuous basis, wherein an extruded or laminated relatively elastic and gummy edible product having the shape of a long tape or string is subdivided into a plurality of single portions which are separated from one another by a predetermined distance.
The present invention further relates to a cutting device for carrying out said process.
The invention is particularly advantageously applicable to the food industry.
In the food industry, some products of the type that includes chewing-gum and several kinds of soft toffees, are obtained starting from long tapes and/or strings coming out of a die-plate, laminating rolls or an extruder.
Within this specific gamut of functions, there are found to be very well known machine assemblies known with the name of xe2x80x9ccut and wrapxe2x80x9d, which schematically consist of a die-plate or of laminating rolls, that shape the gummy mass as a tape and/or string, with a cutting device adjacent thereto that is capable of subdividing said string or tape into single pieces, together with a packing machine that packages said single pieces, the tape or string lying on a suitable conveyor that advances on a continuous basis.
The process is generally operated automatically, thanks to suitable synchronisms between parameters given by product advancement and cutting and packaging frequency of the single portions.
According to a form of embodiment known in the art, a device for severing a gummy tape or string consists of rotating or multiple blades located above the string which, moving downwards, carve the material so much that they get to the complete severing to all single pieces.
Such a system has some disadvantages related to its constructive complexity and to the specificity of the product itself which, soft and sticky as it is, makes the cutting action complicated, remarkably limiting the speed of execution and the overall productivity of the whole plant.
Italian patent application N. MI97A000027 discloses a device for cutting single portions starting from a tape made of gummy material.
Said device comprises a first drum with a relatively large diameter, located above the conveyor on which the tape of product to be cut advances at a constant speed, and a second drum, with a relatively small diameter, which is located underneath said first drum, exactly in correspondence with a gap between two adjacent conveyors.
Drums are located at a predetermined distance from one another, so that during their rotation in opposite directions, the tape of product is dragged along and made to advance by the outside surfaces of the drums themselves.
The upper drum is provided with a plurality of windows which are located at predetermined distances from one another, whereas the lower drum is provided with just one window.
A blade operates inside the upper drum, and moves following an ellyptical trajectory whose longer axis is perpendicular to the plane on which the product to cut advances. The movement is made possible by a suitable dragging mechanism consisting of a couple of epicyclic trains.
Thanks to a suitable choice of the speed of rotation of the epicyclic trainsxe2x80x94these are directly responsible for the speed of the blade moving along its ellyptical pathxe2x80x94and of the two drums, the blade systematically ends up finding itself in a position that corresponds with the two aligned windows of the drums; by moving through these two windows the blade cuts the product that is underneath it and is held still by the two drums.
Such a severing device has remarkable drawbacks and disadvantages that limit its use.
First and foremost the system is very complicated from the constructive point of view, therefore it is very costly; it has also limits from a purely technical standpoint, as it does not make it possible to reach high cutting rates, that is in the range of 1200-1500 or more pieces produced per minute because of the remarkable mass and inertia of the several components, as well as because of the objective difficulty found in obtaining a synchronism that is perfect and continuously repeatable in time, between the movement of the blade and the rotation of the two drums that have their windows aligned with one another for the two way passage of the blade only for an extremely short time lapse.
Furthermore, the fact that the drums must necessarily come in contact with the severed product in order to push it forward subjects the product to a further and not always desired lamination, with further ensuing risks for the product to end up sticking onto the surface of one of the drums.
Moreover, it should be remarked that the distance between two windows of the same drum, measured as it is on the side surface of the drum itself, univocally determines the sum of the length of the product after cutting and of the free gap between said product after cutting and the long tape of string advancing on the conveyor.
Consequently, a machine of this type is subjected to further constraints that limit its practical use: in fact, it is on one side necessary for the peripheral speed of the first drum to be anyway higher than the advancement speed of the tape or string on the conveyor, this in order to make it possible for the severed piece to be removed from the tape or string, whereas on the other side, when an increase in production frequency is desired, it is necessary to have a drum with a greater number of windows, thing that very remarkably increases the drum size itself, consequently its encumbrance and the overall costs of the machine.
Another similar machine is disclosed in document GB-A-2,122,131
The present invention aims at proposing a process for severing and subdividing into portions tapes or strings made of gummy products, particularly in the field of the food industry, that is constructively simple and makes it possible to reach very high production rates.
The above aim has been accomplished thanks to putting into practice the features described in the main independent claim.
The dependent claims outline particularly advantageous forms of embodiment of the present invention.
A further aim of the present invention is that of proposing a device for operating said process.
Said device is described in claim 6, and the claims that depend on it outline some particularly advantageous forms of embodiment of the device according to the invention.
The cutting action by carving the tape or string made of gummy material is carried out by at least one blade; according to a particularly advantageous form of embodiment of the present invention, said cutting action is simultaneously carried out on two opposite sides of the tape or string by a couple of cutting blades that are opposite to one another.
According to an important feature of the process according to the present invention, during the cutting phase said at least one blade, besides being transversally motioned in order for it to accomplish the slitting of the product, is simultaneously motioned along the same longitudinal advancement direction of the tape or string, this at a higher advancement speed of the tape or string of product.
In so doing said at least one blade pushes forward the portion that has just been cut on the conveyor, removing it from the tape or string that advances by a distance that separates the pieces that have undergone cutting, distance that is necessary for a correct functioning of the packaging machine that is located downstream from the cutting device.
Once the portion resulting from the cutting is removed from the tape that advances on the conveyor by a certain distance, said at least one blade is rapidly brought back to its cutting position in order to get a new cycle started, whilst some pushers load the piece of product after cutting over the gap and onto the conveyor of the packaging machine next to it.
According to the present invention, said at least one cutting blade follows a cyclic trajectory having an elongated shape, and this can substantially be defined as ellyptical or xe2x80x9cbean-shapedxe2x80x9d, the long axis of said elongated shape being parallel with the plane of the conveyor on which the product to cut is motioned.
In case the process according to the invention is carried out by a cutting device that has a couple of blades one above the other and mutually aligned on both sides with respect to the product to cut, said blades are motioned along cyclical trajectories that are mutually symmetrical, each of which having a shape of the above defined type that they follow in opposite directions.